You should also use a device like a Behringer DCX2496, not only for xover, but to shape the lower end response of the sealed box and get your ideal target response - it's not usually optimal to accept the natural sealed response curve. Using the EP2500 in mono bridged will give you plenty of power for significant EQ and that sub supposedly has a very substantial amount of excursion(which I wonder just how linear this movement is - this sub is unusually low in cost for these excursion specs - so I am naturally suspicious of it) which would make it very suitable to substantial EQ shaping.
-Chris